This invention relates to the field of pneumatics, and particularly to arrangements for indicating reversal in the sense of the ratio of a pair of pressures of interest.
Proportional apparatus for giving indications which vary with the magnitude of the ratio of two pressures are known. There are, however, occasions when the need is not for continuous monitoring of pressure ratio, but merely for an indication that such a ratio has reversed in sense. One application for such an indication is found in the co-pending application of Erland D. Anderson, et al, Ser. No. 588,291, filed June 19, 1975, and assigned to the assignee of the present application.